While it isn't surprising to see Collected Company showing up in Modern, sometimes the decks that it shows up in are. This isn't the first time that I'd heard the notion of Modern Slivers, but the deck making Top 8 of the Modern Open this weekend in Cincinnati definitely put it on the map in a new way. I can't speak to all of them, but the numbers here suggest that Adam Bowman put a good amount of time into this list:

Monastery Siege is a card that Merfolk has been adopting to beat Lightning Bolt, and Slivers gets the advantage of having this effect tacked on to Diffusion Sliver. It's worth noting that this ability only triggers in play, so if you're worried about targeted removal but not sweepers then you might consider casting main phase Collected Company in search of Diffusion Sliver as a way to preempt removal. The two Blur Sliver and the selection of lords also offer incentives to main phase your CoCos.

I'm not sold on running so many Sedge Sliver and so few Swamp, though the reward is definitely real and you still get a 2/2 sliver out of the card even if you haven't yet found a Swamp.

This deck definitely has more problems with Blood Moon than Merfolk, though the four Manaweft Sliver pull some weight there. They also make turn three Collected Company possible.