3.  To find the SEO plugins for the study –Search 
on the WordPress Website for SEO plugins. 
4.  Sites preparation - Develop the sites; 
5.  To  create  our  microformat  description  –  we 
analysed  the  content  and  decided  the 
vocabularies  &  the  terms  to  be  used  in  the 
microformat descriptions; 
6.  Analyse the sites – Analyse the structured data.  
The following paragraphs give the details of each 
step: 
Step  1:  search  on:  EbscoHost.com; 
Link.Springer.com;  Semanticscholar.org; 
Sciencedirect.com  and  Scholar.google.pt:  We 
searched papers in English, Portuguese and Spanish; 
The search was done on the title with the keywords: 
Metadata; Search Engine Optimization; SEO; Digital 
Marketing;  Wordpress;  Semantic  Web; 
Microformats; Interoperability; Resource Description 
Framework  (RDF);  Vocabularies.  The  search  was 
performed between May 2019 and December 2019. A 
total of 221 articles were collected, 80 of which were 
considered relevant and a total of 31 were selected. 
We  rejected  articles  dealing  with  outdated 
technologies. 
Step 2: To study each plugin we needed to work 
in a common setting so that we then could compare 
the  results  of  each  analysis.  We  created  a  fake 
company  “Marketing  Digital  Tools”  (MDT) 
(http://marketingdigitaltools.com),  and  a  content 
template for its website presenting the company and 
an e-tailor type of shop that sells online services (e-
commerce)  of  site  building.  MDT  seeks  to take  an 
innovative  approach  by  converting  its  services 
through the creation of integrated and discriminated 
service packages, for online sale. 
We created different types of content so to have 
diversity of information: 
  Definition of the organisation: (i) Description, 
Name, Image, URL, Brand, Mission, Vision, 
Values, Social networks, Contacts, Opening 
days & hours; Maps & Geo-coordinates; (ii) 
Founder & CEO: Name, Image, URL, Social 
Networks, Contacts; 
  Description  of  the  Services:  Description, 
Images, Brand, Price, Rating, Contact Point; 
  HowTo: Name, Description, Images, URL, 
Steps, Total time, Estimated Cost; 
  Videos: Description, Thumbnail image, 
Duration, Date of Publication, URL, Author, 
Upload Date;  
 
9
 See https://www.dublincore.org/specifications/dublin-
core/dcmi-terms/ - Accessed in May 13, 2020 
10
 See https://www.w3.org/TR/json-ld/ -Accessed in May 
13, 2019 
  Blog:  Content,  Article  Section,  Headline, 
Image, Alternative Headline, Publishing Date, 
Modified  Date,  Language,  Type  of  Content, 
Copyright  holder,  Copyright  Year,  Place  of 
Publication,  Comments  Count,  Accountable 
Person,  Author,  Creator,  Publisher,  Sponsor, 
Keywords, Genre; 
  FAQs: Title, Content, Author, URL. 
Step  3:  The  search  was  done  in  the  WordPress 
Website. We used the keyword "SEO" and only chose 
the plugins that were: (i) compatible with WordPress 
V 5.3.2; (ii) Free or Freemium, and (iii) in English. 
The  search resulted  in  a total  of  3582  plugins. We 
analysed  each  plugin  reading  its  descriptions  to 
understand if the plugins were within the scope of the 
study. We ended with 85 plugins (see the spreadsheet 
“ListOfPlugins.xls”  in 
http://doi.org/10.5281/zenodo.3830889).  This  file 
presents  the  plugins:  the  first  column  has  the  ID 
number of the plugin, the second denotes if the plugin 
works with microformats, the third the name, the 
forth  a  description  &  notes,  the  fifth  the  version 
analysed, the sixth the last update of the version, the 
seventh the active installations, the eighth the average 
rating and the last column the number of voters).
 
Step  4:  We  replicated  a  WordPress  site  with  the 
contents  described  in  Step  2  as  many  times  as  the 
plugins to be studied (85). We installed one different 
plugin on each site. And created the microformats of 
the information described in Step 2 with the plugin 
user-interface.  
Step  5:  We  created  our  view/description  of  the 
contents using JSON-LD (see Section 4) as mark-up 
language. 
Step 6: We studied the microformats created by the 
plugins. The goal of the analyses  was to  study, for 
each plugin:  
  The vocabularies used (e.g. http://schema.org, 
dcterms
9
), the terms (e.g. 
http://schema.org/organization)  used  and  for 
what; 
  The  mark-up  languages  used  (JSON-LD
10
, 
Microdata
11
 or RDFa
12
). 
The  analyses  was  developed  in  a  Descriptive 
Research  approach,  according  to  the  Case  Study 
method  through  which  presentation  tables  are 
developed, for the organisation of the collected data, 
for  later  appreciation,  comparison  and  publication 
(Zainal, 2007). 
11
 See https://www.w3.org/2012/pyMicrodata/ -Accessed 
in December 20, 2019 
12
 See https://www.w3.org/TR/rdfa-primer/ -Accessed in 
December 20, 2019