The first message needs more then 'Hi!'

That first message, following a connection acceptance, needs to say more than 'Hi!'

The message you write is important and 'Hi!, Hello or Yo Chika!', no matter how polite or well intended, on it's own, means little.

If you've managed to link with someone, it's generally because you want something from them or you need their attention and you want a positive response, so you need to give them more.

If you've met them before or have a mutual acquaintance; tell them. If you have a great business idea and want them involved; tell them. If you're looking for a job; tell them. Tell them what you can, to gain their interest, dont just send a single word and hope for a positive outcome and worse still, dont send that same single word multiple times, no one wins that game.