Applying the well-known saying: buy or you’ll be bought, Yahoo Inc. got back to business Tuesday after rejecting on Monday, Microsoft’s $44.6-billion takeover bid and announced it had purchased a broadband video start-up, Maven Networks Inc., for $160 million. Meanwhile Microsoft announced Monday its own purchase of Danger Inc., a Palo Alto company that makes software for mobile handsets.

Six-year-old Maven Networks, in Cambridge, Mass. include customers as CBS Sports, Sony BMG and TV Guide and is specialized in helping Web sites show online video and insert advertisements in those clips. This will expand Yahoo’s existing relationships with web publishers. In fact, Calif.-based Yahoo is not at its first acquisition of this kind. It is already known that Yahoo also bought firms like BlueLithium and Right Media Inc., also online advertising networks.

Maven does not sell advertising space, but has developed ways of providing an overlay of advertising on Web video clips, or embedding an ad element into a video that a user can interact with.

“They have started making inroads into new kinds of formats that we can utilize to make video advertising much more compelling over time. Our selling capabilities can layer on top of that. There’s lots of demand. Lots of advertisers want to get into video ... but how do you aggregate more supply,” said Tim Cadogan, Yahoo’s senior vice president of marketing products quoted by Reuters.

Video is estimated to be a major growth area. According to eMarketer Inc., an online advertising research company, U.S. online video ad spending will grow from $1.4 billion this year to $4.3 billion in 2011.

“We think video is going to become the third leg of the advertising stool,” said Cadogan.

This perspective fits Yahoo’s plans. The company has already announced its intention to lay off 1,000 workers in other divisions as part of a plan announced two days before Microsoft’s bid to revive its finances and bolster efforts in domains that promise better financial returns. Chief Executive Officer Jerry Yang has repeatedly stressed the company’s mission to become an important stat page for Internet users and a must-buy for online advertisers.

Employees affected by the job cuts reportedly began receiving layoff notices Tuesday, Yahoo spokesperson Diana Wong declined to comment. However, Yahoo is expected to release additional details about the layoffs late this week or early next week.