Food blogger Peter Chang says a presence on Facebook enables restaurants to get their message across on upcoming events and menu changes, and facilitates interaction between 'fans' of a restaurant's page and its owners. But he adds: 'Sometimes, owners try to drum up business by posting too much information, and it just becomes junk.'

Bissett is not yet convinced that Facebook is the way to go, and is cautious about using Dining Concepts' page on the site for promotions. It could cannibalise their other pre-existing marketing offers, he says.

For now, the company's website is still the preferred channel for reaching out to customers, for one big reason. 'Through our website, we can get online reservations. These reservations total up to 300 or 400 a month, and that's something we can't do via Facebook.'

But many local restaurants have jumped on the Facebook bandwagon and value it as a free and fast marketing tool. Users can click the 'like' button for a restaurant's page and become 'fans'. They will then see all the restaurant's Facebook entries on their 'wall' - the personal page where a user sees postings by friends and groups.

Katie Malone, communications director for Langham Place, is convinced the Facebook phenomenon can generate greater revenue. In May, Malone created a page for the hotel's two-year-old Tokoro restaurant. Last month, she launched a promotion offering Facebook users who became fans a 50 per cent discount on ? la carte items on Mondays.

Tokoro's Facebook page now has close to 300 fans, and since starting the promotion reservations on Mondays have increased from about 20 to more than 100, with revenues on those days exceeding HK$70,000.

'From a marketing perspective, this was revolutionary. We could never do this before,' Malone says. 'Unlike spam or junk mail, the Facebook approach doesn't bombard people with information. They choose to be in it, and it's less intrusive.'

Facebook user Sherman Chan agrees, and finds restaurants' pages more useful than their websites. A cook at the Michelin three-star Caprice in the Four Seasons Hotel, Chan says the site helps her plan her dining schedule. She often sees a new posting by a restaurant about a special dish she'd like to try.

'Restaurants that have a Facebook account also tend to have a website,' she says. 'On Facebook, if a restaurant updates its status, the message will appear automatically on my wall and save me the trouble of checking the website.'

Others in the food and beverage industry are of the view that Facebook is a passing fad.

Esther Sham, chef and owner of private kitchen Ta Pantry, says the benefits of the site are overrated. Sham started a Facebook group in December 2008, just after opening her restaurant. At its highest point the page had 300 members, but the number has since dwindled.

'For the first six months or so, a lot of people joined the Facebook group. I even had friends that I haven't seen since eighth grade find me through it,' she recalls.

'But after a while, many users weren't accessing the site any more and they dropped off. That's how Facebook works: after the novelty wears off, people forget about you.

'Facebook is more like a newsletter than a communication ground with customers. You can post new menus or photos, but most of the time you don't have a real dialogue going on.' These days, Sham logs on about once a week and does minimal updates.

Keeping a page up to date is the biggest challenge for Marina Bullivant, communications director for JIA Hotels, which opened Italian restaurant 208 Duecento Otto in May. 'But if you do it properly, there is a way to keep it alive and thriving. You get as much as you put into it.'

Bullivant is one of three people assigned to monitor the 208 Duecento Otto Facebook page, and each administrator logs on multiple times a day.

'Our goal is to turn it into a lifestyle site,' she says. 'Eventually, we'll want to post not only information about the restaurant - like recipes or competitions - but also give details about upcoming events in the neighbourhood of Sheung Wan or even comments about arts, movies or travel.'

Even when a Facebook page attracts a large following, there is no guarantee it will translate into more visits to a restaurant - and many fans may never pop in for lunch or dinner at all.

Among the 270 friends on 208 Duecento Otto's Facebook page, many are not even Hong Kong residents.

'There's a wide reach with Facebook. We have friends who live in Bali or Vienna. They are not necessarily Hongkongers, but they do travel here and give us their support,' Bullivant says. She speculates that non-residents want to keep up to date with what's going on in Hong Kong.

Sham points out that many of the fans on Ta Pantry's Facebook page aren't customers. 'There's a difference between fans and customers. About half of the people in [Ta Pantry's] Facebook group have never been to the restaurant. They tend to be younger, in their early 20s, and are just interested in the food. But at HK$550 per head, the restaurant could be a bit beyond their price range,' she says.

If a Facebook page helps restaurants gauge the demographic of potential customers, it is also a place where they can expect feedback, good and bad.

'Recently, I asked La Creperie in Wan Chai if they have far Breton and they said they do,' Chan says. 'Other times I leave a complimentary note if I see something that looks good.'

Chang warns that Facebook users should be cautious about the legitimacy of comments on some restaurant pages. 'I only trust comments from certain people I know,' he says. 'There are too many fake reviewers out there, or people whose palates aren't really sophisticated.'

Chan says she recently 'de-friended', or dropped out of, the group for Mr Taco Truck in Quarry Bay, despite stellar reviews on its Facebook page, after having a disappointing meal there.

Bissett says: 'My personal view is that people are more likely to post negative comments. We don't respond to any comments on Facebook, particularly the negative ones, because it can become provocative.'

Bullivant says they make it their policy to respond to all comments - good or bad.

'Negative comments are always something you'd rather not have, but it's even worse to delete it. What it does is give us a chance to respond, and at least we know what people are saying about us.'

Despite the popularity of Facebook, Bissett is aware that other, newer technologies are just around the corner.

'Recently, for example, there's been a lot of cellphone-based technologies that have approached us to do promotions,' he says. 'Who knows which one will work out? But I can say that we now have a little blue Facebook icon on our website ... Twitter is looming on the horizon.'