Twitter revenue is growing at 20% y/y as of last quarter, not 5%.
This is, afterall, the problem that sparked all the acquisition talks
According to the poster, the growth rate is 20% not 5%. Either way, to ball park acquisition price, you can divide growth rate by 10, add 1, then multiply in yearly revenue ((growth% / 10 + 1) * revenue). You can also divide growth rate by 10, double it, then multiply in yearly revenue ((growth% / 10 * 2) * revenue). Those estimates assume profit margins of 30%, so if you want to have it all be a multiple of profit, then divide the multiple by 0.3, then multiply that into yearly profit ((growth% / 10 + 1) / .3 * profit --or-- growth% / 10 * 2 / .3 * profit).
I just use (or avoid using) facebook for totally different reasons than I use twitter.
On twitter I mostly communicate with people I've never met and have little association with apart from shared interests. It's a great way of meeting new people.
Facebook is for communicating with people I already know, many of who are actively searching for alternatives but because "everybody uses it" are locked in.