reply with a hi back. maybe inquire as to why u chose that particular profile pic.

i'd say Henloo

Ignore it. Don't take it personally. I just don't want to make friends online at this point. Got burnt a few times. And just a Hi is no incentive for me to reply. A corny opening line won't help either. I get too many of those, so your message does not stand out. If you actually want to interact with me, be consistent about following my posts. Comment on those. That's how I get familiar with you. Then, if you inbox me personally, I might respond.

I'll be happy to reply back

Sorry, ignore the message

I wouldn't respond

Say, Hello!

Send hi back

Get creeped out apparently.

Send two dozen pictures of my shlong