Last week, I issued my annual reminder to blog owners, to consider their blog holiday decorations with care. That reminder mainly focuses on the more controversial issue of blog hijacks, and computer hacking. Besides the long term and subtle computer hacking, your readers, visiting your blog decorated with the latest animation, will have a more immediate and obvious problem to consider - browser freezes and other computer overload problems.
Besides the blatant blog hijack threat, there's another challenge from the animation, for you to consider. The animation - falling hearts / leaves / snow - requires intense processor activity. Every time one heart / leaf / snowflake changes position on the screen (ie, "falls"), the processor has to redraw the screen, with the heart / leaf / snowflake in the new location. Similar to one Designer Templates problem, many computers will run a bit slower when displaying a blog with decorative animation.
People who publish blogs, that are appropriate for these decorations, tend to have readers who may not have purchased a new computer for a couple years. Older computers tend to be marginally able to deal with the load generated by the latest browser updates and other newer software - and adding animation on your blog may be just too much extra load.
Similar to the effect from blog owners who install automatically playing background music, your visitors may decide that reading your blog makes just too much trouble for them.
If people stop visiting your blog, because their browsers freeze up, you'll need to revisit your decorative decision. Maybe, thinking about it now is a better idea.