Visual Website Optimizer started as the easiest A/B testing tool (it still is!), but there's a lot of features now. From cross domain tracking (that requires 3rd party cookies) to geo-behavioral targeting with 15+ variables to heatmaps. It's actually becoming a very comprehensive analytics and optimisation platform. Here's the full feature list http://visualwebsiteoptimizer.com/feature-list.php

Not sure if I answered your question, but the gist of my response is that features add lines of code. There's frontend, backend, test cases, housekeeping scripts, monitoring, etc.

Yes, thank you for the writeup. That page sums it up: a lot of features!

Do you write code for a living?

Not that much. Sorry if it sounded like a snide remark. I just thought the number was big and was trying to understand what those 80 modules of 10000 lines would be.

For comparison, Python 2.7.4 seems to have 400K lines of Python code.

    C:\Users\me\Desktop\Python-2.7.4>cloc .
        4233 text files.
        4130 unique files.
        1424 files ignored.
    
    http://cloc.sourceforge.net v 1.58  T=23.0 s (134.3 files/s, 54205.3 lines/s)
    -------------------------------------------------------------------------------
    Language                     files          blank        comment           code
    -------------------------------------------------------------------------------
    Python                        2086          86198         107060         414941
    C                              548          50019          36839         369130
    C/C++ Header                   254           6514           9919          64470
    Bourne Shell                    39           6109           6235          38030
    m4                              19           1585            191          15172
    Assembly                        47           3659           4474          13733
    make                            12            500            360           3043
    HTML                            14            393             11           2336
    Teamcenter def                   9            173            162           2104
    Objective C                      7            102             70            635
    Expect                           7            115            178            545
    DOS Batch                       30             90            102            426
    CSS                              1             97             19            323
    C++                              2             27             18            134
    vim script                       1             36              7            106
    Javascript                       2             15             10             97
    XML                              4             57              2             73
    NAnt scripts                     2              1              0             30
    IDL                              1              0              0             24
    Visual Basic                     2              1              1             12
    YAML                             1              2              0              6
    -------------------------------------------------------------------------------
    SUM:                          3088         155693         165658         925370
    -------------------------------------------------------------------------------

Python is a programming language. It's very strict. If you give it the wrong input, just one character. You get an error. Software that people use? Is a kind of programming language. Except their "programs" is input into the keyboard. To handle a lot of exceptions without crashing? That will make increase a code base 10x.