It is a truth universally acknowledged that every single reviewer in possession of good knowledge chooses Flickr over Picasa. Flickr is way better than Picasa is most respects, but of course this is not to say that Pisaca is junk! There are some great features in Picasa, with the added advantage that it has a small learning curve and a download button!
If the last part of the above paragraph took you by surprise, let me recap a bit. I have been a big fan of Flickr for a long time now, and being an avid photo-enthusiast have a "pro" (paid) membership on Flickr. However, it has been very difficult for me to convert my friend Shubhasish (a Picasa fan) to Flickrhood. Just as my discussions on comparative advantage of Dual degree over BTech hits a road-block when the issue of Mess Food crops up, my monologue on the greatness on Flickr unfailingly gets him to ask: "But how do you download an Album/Set on Flickr?"
Flickr does not have native set download feature, but there are many third-party apps that offer the functionality. I promised to send over a link of one such good service, but I knew my job won't be easy. This was somewhat like comparing apples to oranges (linguists, please come up with something better. I am sick of using this apple-orange analogy over and over again). While Shubhasish shares all his photos publicly, I prefer to keep my private photos private and share only generic photos with the rest of the world. Thus while sharing my photosets with him, I usually pass him on a "guest pass", which allows him to access the private photos uploaded by me. Now were I sharing all my photos publicly, it would have been easy for me to pass on the most easy-to-use software to download Flickr photos. Dozens exist is the market, allowing users to download high resolution images from public albums/sets (some even allow downloading private images from own sets after authorization). However, referring a software that does the apple-apple comparison so well but fails to satisfy the purpose (of being able to download the whole set in one go) would have made the dialogue complicated and done little to set the scores once and for all. What I was looking for is a software that can recognize a guest pass and authorize the user to download the set. While the debate continued, I gave myself a TwentySecondGoogle challenge but was unable to find it. I saved my energy for the time being and moved on.
Later, while ego-surfing the web (not in the traditional way, but for my own ego...How dare he compare Flickr with Picasa! Huh!), testing softwares one after the other, my hanging suspicion soon became a confidence that it you can't teach softwares to recognize guest passes. So my search space was reduced to software codes that work inside the browser itself: Firefox extensions and Greasemonkey scripts. There was light at the end of the tunnel, and soon I stumbled on to this cool hack (thanks Juan). Quite surprisingly, in order to download the set, you need both Firefox extensions and Greasemonkey scripts. Assuming most people I get in touch with are already on Firefox, it requires three additional softwares/plugins/codes to set the show. But once done, I was impressed with the effectiveness of the hack. Just in a matter of one or two clicks, you can get the whole set on your hard disc. It just made life so simple. A native support of photoset download from Flickr would have been great, but this hack goes miles to show how robust Flickr's API is. I was quick to refer Shubhasish to the trick, which he promised to try.
Coming back to the issue of who's better, a true Flickerian wouldn't want to get into the debate because even as of today, Picasa is way-way behind Flickr. Picasa is just a new kid on the block. If Flickr is a country with centuries of glorious history, Picasa is hamlet settled a few weeks back. It is easy for people to compare storage space, navigation options, integration, etc. between the two services. In fact some may find them comparable. However there's something about Flickr that's totally missing on Picasa: The community experience. If you are on Flickr, you feel so much as a part of a rich and vibrant community of photo-enthusiasts. It is a lively place to be in. The whole world of Flickr is built around sharing and discussing wonderful photos. Picasa, with its best integration feature, is as good as a folder on your computer. You have great access and control over what you have, but there is complete isolation from the world. There is no way of finding out what "interesting photos" your neighbours are coming up with. There is no way of having a lively discussion on a particular photo. There is no way of getting a photo recognized as a great snap. There is no way of finding out the capabilities of your camera. Yes, there is a learning curve associated with it. It is akin to understanding the customs and laws of the nation as against those of a small village community. Picasa would grow, I am sure, and probably one day challenge what Flickr is. We don't know who will win. But even in these days of fast changing internet landscape, I am sure that the battle is still years away.
TwentySecondGoogle: A trademark formula used by me. If I am searching for something specific on Google, and can't find it in the first 20 seconds, there is 95% chance that I will never find it, and very likely, the thing doesn't exists in the indexed web.