There seems to be some automated spam attacks happening today. We've always been dealing with this kind of thing and improving the site's robustness to spammers, so it's not surprising, it just does not normally surface so visibly.
Getting more moderators to help is not practical, since using manual work to counter automated posting is a waste of time. Also given we get hundreds of signups every day, human-approving each one is also a waste of time, and probably not actually accurate anyway since you don't know if someone will spam until they start posting. It has to all be automated. We already have link filtering systems which are pretty effective and basically make spamming pointless since it can't include any kind of clickable link, but I think spammers just set automated systems loose and don't really care what the consequences are.