TripAdvisor last week consumed LaFourchette to make a big move into online reservations against OpenTable, and Google gobbled up Appetas to battle with Yelp and raise its game with restaurants looking for more marketing presence online. Now city guide app Yelp is also biting back: today the company is announcing a new, free Yelp Reservations service.

Incorporating technology from SeatMe, an OpenTable competitor it acquired last year, Yelp will now offer restaurants the ability to take bookings with no fee paid — as long as the restaurant has “claimed” its Yelp profile page.

As a point of comparison, SeatMe’s normal service, which sits on a restaurant website, is charged at $99/month.

“Reservations is a free and simplified form of SeatMe and they’re essentially different products,” a spokesperson tells me. SeatMe will continue to operate as before.

But it looks like Yelp Reservations will offer at least some of the same features as the paid SeatMe service, including the ability to accept invites and alert customers with confirmations. And it will let restaurant owners run the free reservations service via a widget — meaning that it appears to be competing directly with Yelp’s own paid product on a basic level.

Restaurants control the free Yelp Reservations through their Yelp Business Owners Account.

The point of Yelp Reservations seems to be twofold: first, adding another free feature, Yelp’s giving restaurants another reason to come into Yelp’s walled garden. And if Yelp could get restaurants to engage with their profiles on Yelp, there is more of a chance that they will keep details up to date, making the listings more accurate, and also buy into other services Yelp has to offer them. Today, that primarily comes in the form of selling ads and other marketing services on top of basic listings.

“By simplifying the reservation process and offering this feature free of charge to all businesses that have claimed their Yelp business page, we continue to deliver on our fundamental goal to connect people to great local businesses,” said Elliot Adams, a spokesperson for Yelp in London. “As consumer demand grows for the ability to reserve a restaurant online, and business owners look for ways to translate online search results into custom, Yelp Reservations connects the dots to deliver a solution, at zero cost.”

The second is that it will keep those restaurants away from shifting attention to other portals like Google’s, or Foursquare’s, both of which also offer free listings that consumers use to find places to eat. Currently, it looks (at least here in the UK) like Google’s online restaurant listings take you through to other services like OpenTable to make reservations. Google’s acquisition of restaurant site builder Appetas could point to Google wanting to take more control of more features over time.

The idea of adding in reservations to Yelp’s walled garden is also a natural progression of the state of play in the restaurant world today. The idea of adding in reservations to Yelp’s walled garden is also a natural progression of the state of play in the restaurant world today.