Just ask a yes/no question in a FAQ about whether or not a feature exists. The answer to that question is clearly “Yes”. For instance, this question from Google calendar’s FAQ:

Can I check my calendar information via SMS?

Clearly I can check my calendar information via SMS. I don’t see another question saying “Can I check my calendar information via carrier pigeon?”. The reason I don’t see this question, is that I can not check my calendar information that way, and Google isn’t typically going to put a FAQ item out there to tell people what they won’t do…FAQs are as much of a marketing tool as a way to disseminate information.

So the answer is yes, the real question is how would I do that? Click the link and find out. Kind of makes you wonder why they don’t rephrase the question as “How do I check my calendar information via SMS?”