While on the scale of the SL economy $L10 can go a lot farther than a nickel, it does seem a bit parsimonious--not because I don't appreciate it, but because they made such a big deal of it, with the e-mail, the blog post, etc. Building up an expectation like that, with the requirement that recipients log in within a certain period, makes it more obviously a ploy to boost login stats than any real gesture of appreciation.
That's my two cents anyway--or five lindens, if you prefer.