Does “the market” not mean meme stock investors in this instance though?

If you want to look at facts (these come from yahoo finance): 36% of their stock is held by institutions, another ~9% by insiders. Ebay is 95% held by institutions (that sounds insane but I don't follow markets, maybe its normal) and it went up 11% yesterday. That sounds like institutional traders think this is real, right? Ebay is at or near an all time high so why would anyone want to buy at an all time high? Maybe this is a pump and dump on ebay by Wall St? Get retail traders hyped, your stock bumps 10% or more, then dump shares.

I don't understand how a smaller publicly traded company can buy a larger publicly traded company. Don't they need to have a majority of shares or enough to demand a board seat? A deal like that probably needs to have outside investors and/or some leverage of some kind.

That depends on what you mean by "meme stock investors". Retail probably doesn't move an $11 billion market cap company 7% over the 5 hours BEFORE the WSJ article drops. Institutional investors trading on Gamestop's volatility might, though. There are other options, too, but those get into unpopular conspiracy theories and I don't want to nuke my karma.

Headline-driven market is a thing, not sure why meme stock investors are part of this? How are they connected to this news?

Also, what's a meme stock? How would you define that?