It should even but up for discussion that Google’s logo has been, and is currently, a geometric one. The logos use typeface exclusively, and have a very clean/neat look because of it. The old new old logo uses a serif font, which almost gives it an organic feel (as compared to the sans serif) due to its irregularity. Additionally, the lines that make up each letter are not a consistent width. Slight irregularities and minor complexity are not enough to make the old logo appear to be truly organic though. The new logo has very symmetrical lines/curves; the “G” and “e” both look like they would create a perfect circle if the lines were to connect. The consistency in line width also adds to the very plain and geometric aesthetic.
There is virtually no abstraction in the two logos. It could be argued that the word “Google” has some abstract meaning that relates to what the company is, but the image itself doesn’t facilitate abstraction. They are more representational than abstract. Due to the logos only being colored typeface, they are just a representation of the company. The logos are almost more of a visual representation of the company/search-engine, as people have associated the word with being a search-engine, than it being the title of the company/engine, but it still remains that the logos are more of a representation than an abstraction.
The only real differences that I see in the new logo, as opposed to the old, is that it has become more geometric and has a cleaner look. This was probably the reason that the changes were made, as it has made the logo look more like a logo (as opposed to a colorful word).
The geometric and non-abstract aesthetic, with the primary colors, make the logo have a look akin to children’s toys e.g. building blocks. Children play and are curious by nature. Google is a search engine that allows people to explore the internet and play around, so I think that the theme suits Google perfectly.
When it comes to mediation, it’s hard to say, because the image does not really look like an image. The first logo does look like a typeface that someone picked in some word-processing program, which shows a virtually no mediation. However, the new logo looks more like a drawing, which shows to me it has at least some amount of mediation.