It'll be interesting to see what that does to their hiring and retention, though. They are competing for people with Facebook, Google, etc. They weren't previously giving out those options to be nice.
And instead of paper options they will have to increase real $ - part of the problem for them is the way options are treated from an accounting perspective when in fact not all options get exercised.
I think Twitter was actually already giving out RSUs, not options. But either one dilutes the investor share of the company, which will push stock price down.