Tower’s explanation of blobs is kind of strange and not really correct. In a general sense a binary blob is just a situation where you have open-source software that is combined with proprietary components.
Most relevant example to the meme is that the Linux kernel is open-source, but can sometimes contain drivers that are proprietary and don’t have source code available. Those proprietary drivers would be the blobs.
As a counter-example, the linux-libre kernel that devfuuu linked to, is a version of the Linux kernel that has had all the blobs removed.



I could be wrong, but if I remember correctly, the Thinkpad x61 was the last version to ship without Intel ME, and I assumed the meme was a nod to that.