In the latest sign of fantasy sports’ ability to swim in the mainstream, Compete.com released last month some stats on the Web habits of fantasy players.

Compete drew results from a panel of “more than 2 million” Internet users based in the United States for the month of September, compiling numbers on daily reach, search habits and time spent on various fantasy sites.

The fantasy sports subdomain on Yahoo! and the games subdomain ESPN.com, respectively, came out as the clear top two in unique visitors, each more than doubling the next ranked URL. Worthy of note, however, is that NFL.com’s fantasy area came in third, even if you were to combine the results for each of the three ranked CBS Sports subdomains (football, baseball and college football).

Streak.espn.go.com led the way in average stay, checking in at nearly 5 minutes more than No. 2 fantasy.nfl.com. That URL, of course, takes surfers to ESPN’s Beat the Streak game, which won a Fantasy Sports Trade Association award for 2009. FleaFlicker.com and fantasy.foxsports.com followed in that category.

RTSports.com led the way in visits per person for the month at 20.56. Only two other sites beat Compete.com’s overall tally for the category (14.71): baseball.cbssports.com and myfantasyleague.com.

Other data points drawn into focus in the Compete.com release were:

- Unique visitor numbers don’t tell the entire story. Fantasysports.yahoo.com was the top site for UVs in September (6,115,530) but “attention” increased 130 percent — still not bad, while fantasy.nfl.com attention increase by 370 percent. Perhaps the increased focus on video at fantasy.nfl.com is behind its relatively higher attention.

- For search, ESPN was the clear winner for September. It captured three of the top five search-share positions: “espn” was the number one keyword sending traffic to the fantasy category, “espn fantasy football” was the number two keyword and “espn.com” was number four.

- Fantasy players drop off as the season wanes. Baseball.cbssports.com, which reached its season high in April of 516,761 UVs, was down to 347,416 in September with attention down (44 percent) and visits per person down (25 percent) from August. It’s likely that many players lose interest as they move out of contention and content related to the next fantasy season emerges (football, hockey and basketball). Wise brands should track these trends and use the insights to drive campaign creative and media buying.

More results can be found in the table below …