The app is free, supported by ads, and available through the Apple Store. Once you've downloaded it, you add a bio and select interests. The choices, however, are basic. It's hard to project a love of TS Eliot and a weakness for dirty martinis by ticking boxes that say respectively 'books' and 'nightlife'. Your profile complete, the screen opens to a grid of (mostly) faces, with a green light by anyone else online. You might seek out connections by filtering peers according to age, sex, interests, or geographical proximity. Or, Simkhai suggests, you could use it as a 'social compass', by looking at the 'heat' map which shows hotspots where Blendr users (Blendrists?) are, and then joining them. 'You
might have been going to a gym for years, but
never spoken to anyone,' Simkhai continues. 'With Blendr you might find someone who shares your passion for spinning and also for pets, so you can go and introduce yourself with something to say. Or you might be in a supermarket line, and discover the person next to you also loves hiking...'