Promoted tweets aren’t just for big brands anymore, it’s now becoming clear. StylePage.com, a month-old Silicon Valley based start-up for all things fashion, tapped Twitter to build some launch buzz and pad its community membership as it aims to take on the top names in online fashion. A big challenge for vertical social networks like Stylepage is building a critical mass of users at the outset. Could Twitter get it off the ground?

StylePage.com is a self-funded invite-only network of fashionista bloggers run out of a garage in Palo Alto, so we learned from Googling around (the “About us” section of the site is devoid of such trite detail). A decade ago a start-up with a good idea would collect a big fat check from VC backers and then turn half of that over into its online marketing budget.

Looks like the StylePage team had to be more judicious. On April 13 the network launched with a few hundred invited bloggers and about 10,000 twitter followers. Today StylePage has over 22,000 Twitter followers and a growing and enthusiastic user base. How so?

StylePage used Twitter at the right time and it rode on the excitement of its own users. At the time of its launch, a number of high profile Silicon Valley types (possibly StylePage’s angle investors) started spreading the word through Twitter. A month later @StylePage promoted a tweet thanking their followers for the successful build-up, which prompted another boost in Twitter following. Now StylePage boasts over 10,000 visits to its network with over 32,000 fashion photos posted.

The key to success is probably due to the particular niche that StylePage is aiming to serve, and Twitter is as good a platform as any here to spread the word in the fashion circles. Fashion friends follow fashion friends, the idea goes, so when recommendations for StylePage come through the Twitter feed it hits a lot of the right people (see image below).

The community-building feel to StylePage’s strategy even trumped an established fashion brand on the other end of the spectrum. Old Navy launched a #OldNavyBaby promoted tweet for a toddlers clothing sale on May 13, and its Twitter following saw a respectable jump in followers from 41,500 to 43,500 (see graph below).

But Old Navy’s numbers don’t compare. The difference here is that Old Navy promoted a coupon and StylePage promoted a fashionista lifestyle community, so StylePage’s members did most of the heavy lifting of making sure the relevant online community got the news and got involved.

Final Word: Promoted tweets need not be for big players anymore. Twitter’s Dick Costolo told the press that small business would be a big target for it this year. Used properly, aimed at the right community at the right time, a promoted tweet can bring niche networks of people around a brand. You just have to get them involved. The -ista suffix doesn’t hurt.