[gravity13]

Hm. I hope this comes across as constructive criticism, but I'm not sure the visualization type matches well with the data you are presenting.

The movement of the bubbles doesn't seem to convey any useful information, it's just added flare. I'd get rid of it. (you might enjoy some classic books by Edward Tufte too)

The placement of the bubbles seems to be completely random. You can use your space more wisely.

You are trying to represent growing trends with this visualization, perhaps some sort of component should go into representing that. Maybe you can represent that in your x and y plane somehow?

You're viz looks blurry on retina screens. You can fix this by setting the width attribute of your canvas element to twice what you want it to be, and adding a css style width at what you want the width to actually be.

Edit: I just read the text describing what velocity actually does, nvm, I'm dumb.

[amtmz]

Thanks for the criticism! This was my first time doing data visualization, so any feedback is really helpful. I'll definitely check out some books by Professor Tufte.

[underwater]

Even with the desc option it doesn't seem that great. How about using color instead? Recent topics could be brighter.

[hnriot]

agreed, this is basically a tag cloud with the addition of movement that serves little purpose. visualizing textual summaries is not a solved problem, the word cloud was the web 2.0 attempt but I don't believe anyone has really solved the at-a-glance textual visualization problem yet.