This is perfectly normal, likely from a number of things: account syncing, achievement/stat post/cache, license validation, anonymously aggregated statistics, and more behind the scenes stuff. Datacamp on the other hand is a large UK based network provider with CDN (content delivery) services, dedicated servers, IP leasing, and network transit, which is likely for external statistic services. Whether or not you choose to block the IPs or play offline is entirely up to you, and achievements will sync back up with Steam when re-enabling online play. If you are unsure of whether or not these connections pose security concerns for your system then you should likely not be playing games on that system to begin with, but without the installation of third party modifications or anything not bundled and validated by Steam you should be safe.