148 is the h-index, which is defined as the maximum value of h such that the author has published h papers that have each been cited at least h times. (from Wikipedia).

My h-index is 13.

is 148 high ? low ? What does in intrinsically measure (beside being a competition of who piss further) ?

Yes it is high. It means you published at least 148 paper each of it cited by more than 147 times. It is supposed to measure how much interesting/useful work you do.

So if you publish a single paper that only gets cited a few times, it'd completely drag you down. That doesn't seem so great honestly.

No, that wouldn't affect your h-index at all.

If you had sixty papers that have each been cited more than sixty times, you'll still have those sixty papers even if you publish a new paper that gets cites only once.

It's very high vs comp sci. 50+ in comp sci is amazing.

its quite high, its hard to compare different fields since in a more active field papers will get cited more often. George Whitesides, one of the most cited chemists is at almost 270.