Birbimg was launched around two weeks ago.
For now, its KPI is daily impressions. To improve daily impressions, I look out for posts on other social networks that mention specific Twitter accounts. I then reply and link to the respective Birbimg gallery. It's harder to find recent posts than I expected. Many social networks also disallow commenting on posts after a while.
Anyway, growth isn't consistent, but there seem to be organic, returning visitors (~30 visitors/day). Additionally, whenever I catch a new opportunity to share a gallery link on a post that's frequently visited there's a spike in visitors. I hope that every time I do this, a share of these visitors will remember the site and turn into long-term returning visitors.