It would be ridiculous to just tweet and believe its enough.Our mothers are very important pillar of strength and on such a day even calling might not be enough, you need to something special and nice for mother.
You "need" to, in the same way an engagement ring "needs" to be diamond and cost 3x your salary. Certain things matter!
WTF? We're talking about a PHONE CALL vs a tweet for your mom not spending $20K. If you can't spare five minutes, don't bother with a tweet (unless you're in Iraq, the South Pole etc.)
If so, why not do this on your birthday, which seems like it would be a wildly more appropriate date? :P