Steam Winter Giveaway 2015 (D14 - Giveaway Epilogue)

You get to keep them from round to round. Basically it just means you can drop a ton of points later and overpower other bidders who already spent some of theirs or spread them out (sort of like what happened with the last round), but you risk on losing out on games you want if they're popular.

It's all explained in the OP pretty decently I think.