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.
If so, why not do this on your birthday, which seems like it would be a wildly more appropriate date? :P
And of course you don't "need" to, the sun will still rise the day after if you don't, but certain things matter.
What matters even more is showing your appreciation outside of one designated day a year, or a shiny piece of carbon.
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.)