[gadilif]

Yes, but not efficiently (it will be very slow) and will be hard to detect because of noise (the article mentions the 'cacophony' of gravity noise). This is similar to EM radiation, so, you do frequency modulation (or amplitude, but that seems harder with gravity - you'll need to modify mass...), so you have a base high frequency on top of which you add lower frequency. The substraction later gives you a clean signal (or, Gravity Radio).

[anyfoo]

I'm not sure "slow" matters that much. If (and that's a big if) there is advantage to announce yourself to other civilizations using gravity waves, instead of other means, then it probably does not matter too much if transmitting a reasonable amount of information takes a decade or so. You'd put it on repeat of course, and hope that interested civilizations don't have too short of a lifespan to still make sense of it.

[vbezhenar]

Will you distinguish it from noise? Surely those will be compressed and encrypted.

[gadilif]

Some of it, definitely. But if the purpose is to seek others and announce yourself (like we did with Voyager 1 and 2), then you'll want it to be plain. Also - Public radio transmissions are not encrypted (as your purpose is to have as many listeners as possible... You monetize on ads).