Yes, in many books from EU Holonet was mentioned to be republic(and empire)-wide instant communication network with functions like the TV and internet. Coverage and function varied from author to author though.
it was a very 90s kinda internet, and none of the characters we followed were posters.
one of the smarter things to not go into exhaustive detail about really.
Star wars hexbear and there’s people posting edits of Tusken raiders shooting stormtroopers down with the words “Another SStormtrooper down! Unlimited Battle of Yavin on the galactic core!” splashed over it