The pixel debate is back . Internet explorer out of the box doesn’t permit resizing text measured in pixels, which at the same time is the only reliable way of setting dimensions that produces same result everywhere.

The crux of the matter is simply who should have the final word in how the page is displayed, designers or users?

Personally I think it should be users. After all, it’s about them and if there’s a way for them to make their experience more pleasant or useful without degrading it for others, why shouldn’t they be allowed to do so? Good designs serve, not command.

However, I find it more interesting how many people have no idea what px unit actually means . Pixels, as defined by W3C, are not the same as pixels used to define graphic resolution of a computer, even if they usually seem to be.

For example, if we ever happen to get high-density monitors with say 300 dpi pixel density instead of these days common 96 dpi, then a 15″ display would have a graphic resolution of 3600×2700 dots, but it would still have only 1152×864 pixels in CSS model. Therefore one web pixel would be represented with around 9 graphic pixels.

Well, that’s the theory. In practice there’s a lot of cheating. Monitors have various sizes which are only an approximation of the stated one (15″, 17″ etc.). Operating systems try to pay attention to pixel density, but often don’t or can’t. And so on.

The result of this is that size of displayed text and images is device dependent even when in theory it shouldn’t be. So the only way is also good only up to a point.

Does anyone find margin collapsing useful and if yes, why?

So far they’ve only caused me grief, but there must be something I’m missing.

Yesterday I talked about influence of language and tag design on ratio between the number of unique and all tags. I haven’t discussed why this number would be interesting and what would it tell us.

Let’s start with a simple graph:

Blue circles represent objects. Connections represent tags and rectangulars are pages with hits for a specific unique tag. As we can see, all images but one have two tags (number of connections from a circle) and the most popular tag is attached to 4 images (number of connections from a rectangular).

What ratio tells us is an average frequency of a given tag (how many connections does a typical rectangular have). The higher it is, more hits will be returned by search.

However, tag connections and rectangulars also form a path between objects. Therefore higher ratio also means a better connected graph with (again on average) shorter paths between different objects. For example if we look at the red path on example graph then left top object is at least two clicks away from the top one and at least four clicks away from the bottom right one.

If tag browsing and searching are main methods of exploration, then a loner like the most right circle is practically unreachable and more tags an object has, the better chances it has to be discovered.

Now, I presented a very simplified graph with a fairly even distribution of tags. Normally you wouldn’t have this. A word like cat is far more likely to be used as a tag than something like hippopotamus resulting in creation of super-nodes with far more connections to objects than system’s tag frequency ratio.

With time you’d also expect this ratio to grow. Vocabulary, especially of commonly used words, is far more limited than number of pictures people can take and with time it becomes harder to create a unique tag. Flickr has tens or even hundred millions of tags, but certainly far less unique ones.

Graph topography and things like super-nodes not only skew the picture, they can also change the perception and application use. I’ll write more about how in few months, when there will be more knowing and less guessing.