In all honesty, Bending Spoons acquiring AOL will probably have better synergy across their portfolio than Salesforce buying Slack. Having worked at SF, even working in dev rel/infra ops, it was mostly "slack who?". That acquisition was more like the Skype/Lync - aka, not really integrated, but tried - as opposed to MS buying GitHub and mostly keeping it independent.
In all honesty, Bending Spoons acquiring AOL will probably have better synergy across their portfolio than Salesforce buying Slack. Having worked at SF, even working in dev rel/infra ops, it was mostly "slack who?". That acquisition was more like the Skype/Lync - aka, not really integrated, but tried - as opposed to MS buying GitHub and mostly keeping it independent.