Yahoo’s recent announcement that it is leasing additional office space in Midtown is the latest in a series of Internet firms beefing up their presence in Gotham.

Yahoo’s new lease deal follows an even larger one by its rivals Google and Ask Jeeves and by several lesser known firms.

But the largest brick and mortar deal by any real estate company in the city is from IAC/InterActiveCorp., the owners of Expedia, Home Shopping Network,Match.com, and Ticketmaster. Its Frank Gehry-designed headquarters, now under construction, is set to be ready for occupancy early next year.

In February, the Sunnyvale, Calif.-based Yahoo announced it would take 40,000 square feet of additional space at 1065 Sixth Ave. As the search giant will now have a total of 74,000 square feet at the building on West 40th Street, it will be one of the main tenants there. The move is an effort to consolidate various offices. But Yahoo is also expanding. Its expanded financial journalism group, for instance, has offices at its Midtown headquarters, which is decorated in a purple and yellow color scheme that looks like something ripped from the pages of a Dr. Seuss book.

Yahoo will soon occupy six floors in the building, which has a reported asking rent of $38 a square foot. Yahoo’s move follows a larger deal announced late last year by Google. The Mountain View, Calif.-based company signed on to lease 270,000 square feet at 111 Eighth Ave. at West 15th Street. The company can easily afford it, having raised $4.18 billion in a secondary stock offering – with more likely to come – last year as well.

Indeed, Google’s new Gotham home is tiny compared to its plan to build 1 million square feet of office space at Moffett Field, a former Naval Air Station, now controlled by NASA and a short drive from Google’s headquarters in Silicon Valley.

Separately, Ask.com (formerly Ask Jeeves, now a unit of IAC) is another search engine company that has found office space in Manhattan. It took nearly 17,000 square feet of space at 225 Park Avenue South early last year. Since then, the company has been bought by IAC/Interactive. A company spokesman said she did not know whether Ask.com would move in to the Gehry building.

Other Internet firms signing lease deals in the last year include Keane Incorporated, a technology consulting firm, Harris Interactive, an Internet market research company, and Answers.com, an Israel-based search engine company.

Technology firms, once they reach a certain size, like to build out their own space in a way that fits their corporate culture, Jack Petrie, an executive with Cresa Partners, the real estate broker that represented Yahoo, said. Internet companies tend to favor open plans, greater density, and more common space for lounges, kitchens, and conference rooms.

IAC/Interactive’s hiring of Mr. Gehry to build its headquarters at 19th Street and 10th Avenue certainly makes a statement. The plan is for an oddly shaped 29,000-square-foot 10-story tower that will cost $100 million. The project will allow the multifaceted company to join its half-dozen Manhattan offices.

It’s not far from Google’s future offices on Eighth Avenue, and the Chelsea and meatpacking district’s galleries, nightlife, and restaurants are a lure to the hip, young staffers that Internet companies need to recruit and retain, Mr. Petrie said.