I guess, can't be too good, but how is black supposed to handle it? Was o.k.? (It is supposed somewhere, that black might even tenuki, but let's assume, she want's to answer locally.) Should she simpla connect at a now?
DJ: My feeling is that in the diagram above doesn't appeal to me... may smack of greediness, but it could turn out an effective play.
Bearing in mind that I'm only a 2k, I'd rather play as in the diagram below. I'm not sure whether this is an old joseki, and I do not follow joseki much anyway...
Alex Weldon: Yes, this is joseki.
Andrew Grant: The joseki has extending one space further.
Joonas Tyystjarvi: I don't think a in the first diagram is very good, and instead black should play to prevent white from settling there. I think something like this might follow (but I'm just 2k too, probably someone has better ideas). Note that if at , black can play at , sacrificing the two stones.