Mashable highlighted research completed by eMarketer that indicated massive spending changes in targeted social networks.

Spending on social networking sites is expected to grow 75 percent next year, to $2.1 billion, according to eMarketer, a research firm that tracks online advertising.
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Smaller sites’ share of that money is growing. Of the $920 million spent this year to advertise on social networks, 8.2 percent went to niche sites, up from 7 percent in 2006, according to eMarketer. Next year, niche sites’ share of ad revenue is expected to grow to 10 percent.

Dogster, Inc.’s advertising revenue doubled in 2007 from 2006 and will more than double again in 2008.

Also last week, Auren from Rapleaf, a career-centric community platform, shared some of their data on adult male and female usage of social networks.

The fastest-growing demographic on social networks are moms between 35 and 45 years old. These women are putting up pictures… and using these social networks to essentially make family home pages and share them with friends and relatives. They are decorating their pages, making RockYou slide shows, and using lots of widgets.

On both our sites we see very heavy usage by woman age 25-45. Most return daily and have made Dogster and Catster their hub of sociality.

Finally if you had any doubts as to the value of highly focused vertical online communities, Monster Worldwide (the job company) weighed in last week when they acquired the career-centric community sites of Affinity Labs for $61 million.

Congrats to Chris Michel and the whole Affinity Labs team.