[tpmoney]

Because they're with us everywhere and conveniently at hand most of the time. A traditional computer, even in laptop form, is comparatively bulky, unwieldy and inconvenient. Laptops don't fit into your pocket, they don't pull out for one handed use while you're waiting in line and they don't slip easily back in once the line starts moving again. To type in text, you need both hands free, and a relatively stable surface to place your laptop on.

Phones trade ease of use for ease of access. They allow people to be online and participating in an online discussion when and where a traditional computer would be prohibitive or inconvenient. And as a trade off those people aren't always able to do (or conveniently do) something they would do on those traditional computers. Most people most of the time seem to find that an acceptable tradeoff. And to be fair to those most people, I write far more than I copy and paste links so it's not unreasonable to find that tradeoff to be acceptable.